Calculus Examples

$f (x) = 2 x + 4$

Step 1

Consider the limit definition of the derivative.

$f' (x) = lim_{h \to 0} \frac{f (x + h) - f (x)}{h}$

Step 2

Find the components of the definition.

Tap for more steps...

Step 2.1

Evaluate the function at $x = x + h$ .

Tap for more steps...

Step 2.1.1

Replace the variable $x$ with $x + h$ in the expression.

$f (x + h) = 2 (x + h) + 4$

Step 2.1.2

Simplify the result.

Tap for more steps...

Step 2.1.2.1

Apply the distributive property.

$f (x + h) = 2 x + 2 h + 4$

Step 2.1.2.2

The final answer is $2 x + 2 h + 4$ .

$2 x + 2 h + 4$

Step 2.2

Reorder $2 x$ and $2 h$ .

$2 h + 2 x + 4$

Step 2.3

Find the components of the definition.

$f (x + h) = 2 h + 2 x + 4$

$f (x) = 2 x + 4$

$f (x + h) = 2 h + 2 x + 4$

$f (x) = 2 x + 4$

Step 3

Plug in the components.

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - (2 x + 4)}{h}$

Step 4

Simplify.

Tap for more steps...

Step 4.1

Simplify the numerator.

Tap for more steps...

Step 4.1.1

Factor $2$ out of $2 x + 4$ .

Tap for more steps...

Step 4.1.1.1

Factor $2$ out of $2 x$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - (2 (x) + 4)}{h}$

Step 4.1.1.2

Factor $2$ out of $4$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - (2 x + 2 \cdot 2)}{h}$

Step 4.1.1.3

Factor $2$ out of $2 x + 2 \cdot 2$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - (2 (x + 2))}{h}$

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - 1 \cdot (2 (x + 2))}{h}$

Step 4.1.2

Multiply $- 1$ by $2$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - 2 (x + 2)}{h}$

Step 4.1.3

Factor $2$ out of $2 h + 2 x + 4 - 2 (x + 2)$ .

Tap for more steps...

Step 4.1.3.1

Factor $2$ out of $2 h$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 x + 4 - 2 (x + 2)}{h}$

Step 4.1.3.2

Factor $2$ out of $2 x$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 (x) + 4 - 2 (x + 2)}{h}$

Step 4.1.3.3

Factor $2$ out of $4$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 (x) + 2 (2) - 2 (x + 2)}{h}$

Step 4.1.3.4

Factor $2$ out of $- 2 (x + 2)$ .

$f' (x) = lim_{h \to 0} \frac{2 h + 2 (x) + 2 (2) + 2 (- (x + 2))}{h}$

Step 4.1.3.5

Factor $2$ out of $2 h + 2 (x)$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + x) + 2 (2) + 2 (- (x + 2))}{h}$

Step 4.1.3.6

Factor $2$ out of $2 (h + x) + 2 (2)$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + x + 2) + 2 (- (x + 2))}{h}$

Step 4.1.3.7

Factor $2$ out of $2 (h + x + 2) + 2 (- (x + 2))$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + x + 2 - (x + 2))}{h}$

Step 4.1.4

Apply the distributive property.

$f' (x) = lim_{h \to 0} \frac{2 (h + x + 2 - x - 1 \cdot 2)}{h}$

Step 4.1.5

Multiply $- 1$ by $2$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + x + 2 - x - 2)}{h}$

Step 4.1.6

Subtract $x$ from $x$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + 0 + 2 - 2)}{h}$

Step 4.1.7

Add $h$ and $0$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + 2 - 2)}{h}$

Step 4.1.8

Subtract $2$ from $2$ .

$f' (x) = lim_{h \to 0} \frac{2 (h + 0)}{h}$

Step 4.1.9

Add $h$ and $0$ .

$f' (x) = lim_{h \to 0} \frac{2 h}{h}$

Step 4.2

Cancel the common factor of $h$ .

Tap for more steps...

Step 4.2.1

Cancel the common factor.

$f' (x) = lim_{h \to 0} \frac{2 h}{h}$

Step 4.2.2

Divide $2$ by $1$ .

$f' (x) = lim_{h \to 0} 2$

Step 5

Evaluate the limit of $2$ which is constant as $h$ approaches $0$ .

$2$

Step 6